This application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or 365 to German Patent Application No. 299 02 750.3 filed in Germany on Feb. 17, 1999; the entire content of which is hereby incorporated by reference.
1. Field of the Invention
The invention relates to apparatus for the manufacture of photographic prints, especially a copy of image data of an original which are present in electronic form, by preferably strip wise exposure of the image data of the original onto a photographic copier material. The image data are thereby produced by way of a scanning arrangement and subsequently processed in the image data processing arrangement in order to be transferred into the electronic form which is necessary for the exposure.
2. Background Art
Digital print producing apparatus on photographic basis, so-called digital photographic printers, produce paper prints or copies by recording the image information of the underlying originals which is stored in electronic form onto a photographic copier material. For example, the image information of the original can be optically produced for each image by a digitally operated mirror matrix. Accordingly, an optical representation of the original can be produced and this optical representation of the original copied and thereby recorded on the copier material.
Using the micro-mirrors of the mirror matrix for line by line or strip wise exposure allows for the production of photographic prints of theoretically any sized in the direction transverse to the lines or strips.
Strip shaped portions of the original which in their longitudinal direction extend across the whole original can be respectively optically produced by way of the mirror matrix and sequentially exposed in a corresponding three-dimensional arrangement onto the copier material. The correct spatial positioning of the exposed strips is thereby achieved by displacement of the copier material relative to the exposure light path. This can be achieved by advancement of the copier material or by a correspondingly movable projection optic. The relative displacement is carried out synchronously with the change of the illustrated strips of the original. If the strips are several lines wide, adjacent strips can also overlap, if desired. If the copier material, depending on the degree of overlap, is repeatedly exposed in certain regions, this must be taken into consideration for adjustment of the amount of copier light used in the individual exposure steps. This exposure process is known under the acronym TIG [Time integration grayscale].
Relatively satisfactory photographic prints can be manufactured with the above described methods and the use of a commercially available micro-mirror matrix. However, the manufacturing cost for such an apparatus for the manufacture of photographic prints are relatively high and the speed with which the photographic prints can manufactured is often unsatisfactory, especially when the light intensity per unit area during the exposure is relatively low, so that long exposure times are required.
The present invention now provides an apparatus which overcomes the above disadvantages with prior art apparatus.
According to invention, the apparatus for the manufacture of a photographic print on a copier material includes a scanning arrangement for scanning an original for the generation of image data for the manufacture of the photographic print. The apparatus further includes an image data processing arrangement for the processing of the image data into control signals for the manufacture of the photographic print. An exposure arrangement with a projecting optic for the manufacture of the photographic print is connected to the image data processing arrangement. The illumination arrangement preferably includes a broadband light source, for example a halogen light source, and a filter arrangement which is positioned in the light path between the light source and a mirror matrix for adjustment of especially selected light amounts for selected spectral regions.
While in corresponding prior art arrangements very expensive light sources are often used and the light which is projected by the micro mirrors of the mirror matrix onto a photo sensitive copier material is filtered, it has been surprisingly found that high light densities or light intensities can be produced with a conventional, preferably broadband light source, for example a halogen light source. The exposure with the individual colors of the light spectrum that are necessary for an appropriate exposure of certain image elements can be adjusted with an appropriate filter for different colors and appropriate activation of the micro-mirrors of the mirror matrix.
The filter arrangement which is, for example, a filter wheel, can be provided along its whole circumference with several filter regions for each base color in order to avoid down times and to increase the speed of the apparatus.
A transport arrangement for a light sensitive copier material is provided for the manufacture of the photographic print by the exposure arrangement, whereby the transport speed of the light sensitive copier material is detected or monitored by use of a sensor. The sensor can be, for example, an optical scanner, a mechanical sensor or the like, to detect the actual transport speed of the copier material on the transport arrangement. The measured transport speed of the photographic print is then preferably used for controlling the speed of the transport arrangement and/or the exposure time, or the light intensity by way of the mirrors or the light source. This means that, the transport speed is readjusted on the basis of the actual speed of the copier material, for example by way of a step motor within a control loop, or the exposure time is adjusted by the mirrors of the mirror matrix. Of course, as mentioned above, the brightness of the light source can also be changed, or an additional darkening or brightening arrangement can be provided, for example in an LCD which is shone through, or the like. Of course, the mentioned measures can also be combined within a control loop and not only individually used.
In order to monitor the intensity of the light source both integrally as well as spectrally, a measuring sensor, for example a photo cell, can be provided which integrally or for each individual color carries out a measurement of the light which is not used for projection onto the photo sensitive copier material. In this manner, the power of the light source can be readjusted, or it can be determined when the light source must be changed, for example, automatically or manually. A carousel, a sled or the light can be provided for automatic or manual change, which is activated when the value detected by the measuring sensor is outside the tolerance. On the other hand, for example upon a decrease in the light output, initially more current or a higher voltage can be fed to light source also by way of a control loop, in order to extend the life of the light source, for example a halogen lamp.
The filter arrangement can be constructed as a filter wheel, as an additive or subtractive color filter and the like.